Reevaluating the Necessity of Performing Routine Laboratory Tests in the First Week After Joint Replacement Surgery.

Purpose Routine postoperative laboratory tests are commonly included in clinical paths following joint replacement surgery in Japan. However, with the global trend toward outpatient arthroplasty, the necessity of frequent testing is being questioned. Therefore, this study aimed to evaluate the necessity of routine and frequent laboratory tests during the first postoperative week of patients undergoing joint surgeries. Methods This retrospective study included 201 patients who underwent primary arthroplasty (64 total hip arthroplasty (THA), 85 total knee arthroplasty, and 52 unicompartmental knee arthroplasty) between April 2022 and September 2023. Laboratory tests were performed preoperatively and on postoperative days 1, 3, and 7. Abnormalities in hematologic, renal, hepatic, and electrolyte parameters and whether these abnormalities led to therapeutic interventions were examined. Results Abnormal laboratory values were common, including low hemoglobin levels (79%), elevated C-reactive protein levels (100%), and mild electrolyte or hepatic enzyme changes. However, therapeutic interventions based on these tests were required in only eight (4%) patients. Two patients who underwent THA received allogeneic transfusion, one was treated for hypokalemia and four for hyperkalemia, and one discontinued edoxaban due to suspected liver dysfunction. No interventions were executed based on day 3 laboratory findings. Conclusions Although abnormal laboratory results were frequent after joint replacement surgery, they rarely led to therapeutic intervention. Most abnormalities were clinically insignificant or transient. Routine testing on postoperative day 3 may be unnecessary in well-managed patients, and omitting it could reduce patient burden and healthcare costs without compromising safety. Careful monitoring with preoperative and immediate postoperative tests may be sufficient.